In the following description, particular reference is made to caps made of plastic or other suitable material, wherein by unscrewing or lifting the cap a safety strip is detached or at least distanced.
Caps of the above type not only present drawbacks connected to construction simplicity and fast screwing-on by automatic machines, but also pose a significant problem, common to all caps comprising safety strips, of safeguarding a consumer against illicit opening of the bottle.
Several known caps offer quite satisfactory solutions to this problem, but it has been noted that often it is possible to unscrew a cap very slightly, not enough to break the safety strip (and thus prove that the bottle has indeed been opened) but, on the other hand, quite enough to break the original seal and allow gas, and even liquid, to escape from inside. What is more, and more serious, it would be possible to introduce fluids into the bottle in this way, and all without its being obvious thereafter to a consumer. Especially with plastic bottles, this risk is high, since pressing on the lateral wall of the bottle causes it to function like a suction pump; but the risk also exists with glass or other rigid bottles, which could be totally immersed in a bath of liquid to cause invasion of extraneous fluid.
A principal aim of the present invention is to obviate the above-mentioned drawbacks, by providing a cap which allows no gas to escape from the bottle, nor any introduction of extraneous fluid therein, unless the safety strip has already been removed.
One advantage of the invention is that no extra cost is incurred by its use, nor is cap use consequently complicated.